Light-path-equivalent light splitting prism group device with four split light beams

Abstract

The invention discloses a light-path-equivalent light splitting prism group device with four split light beams. The prism group device comprises a lambda / 4 wave plate, three light splitting prism groups, a polarization array and a detector. Each light splitting prism group is formed by gluing three triangular prisms, and can divide one incident light beam into two beams of emergent light in equivalent light path. After that the three light splitting prism groups are combined, an orthogonal circularly polarized light beam which passes the lambda / 4 wave plate can be divided into four identical light beams, and via phase shift by the polarization array, four interference images are formed in the detector. Thus, the light splitting prism groups of special design is used to split the incident light in equivalent light path, and the utilization rate of light energy is very high. The four beams of emergent light are all parallel with the optical axis, and need not to be collimated by other optical components, and thus, the position matching precision is very high.

Description

technical field [0001] The invention relates to the field of optical interferometric measurement and testing, in particular to a four-beam beam-splitting equal optical path beam-splitting prism group device. Background technique [0002] Phase-shifting interferometry technology refers to a measurement technique that produces phase shifting through the modulation of the interference field, and then uses a certain algorithm to restore the physical quantity to be measured by using a certain algorithm from the collected phase-shifting interference images. Using phase-shifting technology, the phase can be restored by simple point-to-point calculations between interferograms. There is no need to locate the center of the fringe, and there is no need to use algorithms such as interpolation to fit the phase. Therefore, the phase-shifting interferometry technology significantly improves the accuracy and automation of interferometry. degree. Phase shifting methods can be divided into ...

AI Technical Summary

Problems solved by technology

However, the prism in this device divides the incident light into four beams in the horizontal direction, and the shape of the detector is mostly a square or a rectangle close to a square, and the shape of the optical element is mostly circular, so the spatial resolution in many tests is relatively low. Low

And in this device, only three beams of light are used to reconstruct the phase using the three-step phase-shift method, which is very sensitive to phase-shift errors and is prone to errors

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